#ifdef a
//求斐波那契数列的前10项之和
//1 1 2 3 5 8 13 21 34 55
#include<stdio.h>
int Fibonacci(int n) {
    if (n <= 0)
        return 0;
    else if (n == 1)
        return 1;
    else if (n == 2)
        return 2;
    int first, second, third, sum;
    sum = 2;
    first = second = 1;
    for (int i = 3; i <= n; i++) {
        third = first + second;
        first = second;
        second = third;
        sum += third;
    }
    return sum;
}
int main() {
    int sum = Fibonacci(10);
    printf("%d\n", sum);
    return 0;
}
#endif


